This is exquisite! When the light captures the fractures inside it looks like it has little white lights shimmering in it. It has beautiful striations and a little rainbow in it's belly. It has one or two rough bits (obviously the bottom half is very rough as that is where it broke away from a cluster) .
It seems to have a holographic point inside it that belongs to the broken off piece sticking out but it only shows from some angles - odd and magical in equal measure!
This point feels so light it is almost silver to me! It measures about 11cm long x 6.5cm x 5cm deep.